Is there anything cheaper than MagicJack VOIP?

I have a server running all the time, so having a computer on all the time is not a problem. But is there anything cheaper than MagicJack where I can send/receive calls from people’s cell phones? This would require any phone number. Thanks!

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I have a Straight Talk Samsung R451c phone, and I’ve tried calling it from my Magic Jack phone, and my iPod Touch VOIP app, and when I do, I just hear three beeps and then silence. Does Straight Talk block VOIP calls? Is there a way to make it work?

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